Fuel injection pump for internalcombustion engines



Jan. -15, 1952 YfA, GRIMOD 2,582,539

FUEL INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES im' R QMATTORNEY Jan. 15, 1952 Y. A. GRIMOD 2,582,539

FUEL INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES Filed April '7, 1949 4 Sheets--Sheefl 2 Z6' 5 5 2' 32" g y 10/ Z l t. 60 :Q J0

/NvENToR BY mag-3x@ QW ATTURNEY Jan. 15, 1952 Y. A. GRxMoD 2,582,539

FUEL INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES Filed April 7, 1949 4 Sheets-Sheet 5 v 6 I c :B/

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BY ms R GMATTURNEY Jan' 15, 1952 Y. A. GRlMoD 2,582,539

FUEL INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES Filed April 7, 1949 4 Sheets-Sheet 4 RQMM ATTURNE Y Patented Jan. 15, 1952 FUEL INJECTION PUMP FOR INTERNAL- COMBUSTION ENGINES Yves Andr Grimod, Paris, France, assignor to Society La Precision Mecanique, S. A., Paris, France, a society of France Application April 7, 1949, Serial No. 86,042

15 Claims.

The present invention relates to automatic regulation piston pumps, of the kind in which there is interposed, on the path of the fluid to be delivered by the piston, a movable part slidable in a bore and provided, on a portion of its length, with at least one lateral channel permitting liquid to flow therethrough for certain relative positions thereof along the axis of said bore. so that, owing to the hydrodynamic pressures or the inertia forces that are generated, a self-regulating effect is obtained.

The chief object of the present invention is to provide a pump of this kind which is better adapted to meet the requirements of practice than the existing pumps of the same kind.

The chief feature of my invention consists in arranging such a pump so that the relative useful sections of thel bore and of the channel or channels of the regulating moving member can be made variable at will so that it is thus possible to modify the conditions of operation of the regulator, in particular the limit speed.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which:

Fig. l is a vertical section of a fuel injection pump made according to my invention;

Fig. 2 is a separate view, on a larger scale, of a portion of this pump, showing more especially the speed regulating valve member according to my invention;

Figs. 3 and 4 similarly show a valve of this kind made according to two other embodiments of the invention;

Fig. 5 separately shows, in diagrammatic perspective view, a regulating valve member of the kind of that of Fig. 2, engaged in its bore;

Fig. 6 is a longitudinal sectional view of a regulating valve pump made according to a modification;

Figs. 7 and 8 show, respectively in axial section and in transverse section, an injection pump made according to another embodiment of my invention;

Figs. 9 and 10 show, respectively in elevation and in section, a regulating valve. for a pump of this kind made according to other features of my invention;

Figs. 11 and 12 show in diagrammatic section a fuel injection pump made according to still other features of my invention.

The construction of Figs. 1 and 2 is disclosed. in copending application Ser. No. 86,046 filed of even date with this application, by Gaston, Charles Drouot.

A pump according to my invention includes at France April 14, 1948 2 least one piston i for injecting fuel into an engine and a regulating member 2 slidable in a bore 3 provided next to the pump compression chamber-4. The top portion 5 of this member subjected to the action of a spring 6 constitutes a valve cooperating with a seat 1. Cylindrical body 2 is provided with at least one lateral channel 8 or other passage adapted to cooperate with bore 3.

This regulating member is arranged in such manner that the relative active sections of its channel or` channels 8, on the one hand, and of the corresponding distributing areas of bore 3, on the other hand, can be made variable at will in such manner as to permit of modifying the conditions of operation of said regulator.

By way of example, and supposing that channel 8, in the lowest position of member 2, opens over a height h into chamber 4 (Fig. 2), whereas there remains, between the upper end of this channel 8 and seat 1, a distance d, one of the objects of the invention is to make it possible to vary at least one of these two parameters d and h.

It is clear that this variation modifies the conditions of operation.

For liquid can ow from compression chamber 4 to delivery chamber 9, in communication with the engine, only through channel 8, that is to say only after member 2 has already been lifted a distance equal to d. The portion of channel 8 then remaining in compression chamber 4 is equal to (7L-d), which has in particularV the two following consequences:

1. The value of (lt-d) determines the upper limit value of the engine speed. For, from a given speed up. the valve has a tendency, under the effect of the hydrodynamic pressures, or of its inertia, to keep moving upwardly, so as to cut off the communication between chambers 4 and 9; the value of this limit is the lower as the quantity (h-d) is itself smaller.

2. 'I'he fact that there is a distance d between the upper end of channel 8 and the under face of valve 5 causes liquid to be sucked back into chamber 9 when the valve returns onto its seat after the delivery stroke of pitson I. This corresponds to a reduction of the amount of liquid delivered toward the engine, this reduction depending upon the value of d.

As a matter of fact, the section of the passage through which the liquid can ow, when the regulating action is exerted, depends also upon the width left free at the inlet of channel 8 in the. direction transverse to the valve axis, as shown by Fig. 5; this section is represented on this figure by triangle ABC and its value depends both upon height h or (hf-d) and upon width a.

The object of my invention is therefore to pro- 3 vide means for varying this section, either in-the axial direction or transversely to the axis, or again in both directions simultaneously.

It seems advantageous to make these means such that regulation of the section is obtained by a rotation imparted to member 2 about its axis, relatively to the bore in which it is fitted. which bore is provided with cooperating surfaces of suitable shapes.

For instance, as shown by Figs. 1 to 4, at least one of the ends of channel 8, for instance the lower end thereof, cooperates with an oblique edge of the corresponding end of bore 3. In order to rotate member 2 about its axis, it is driven by a control part I4, rotatable by means of a lever |5 and engaging on a kind of screw-driver element I6 carried by the valve head.

Advantageously, member 2 is fitted with at least two passages or channels such as 8 and 81, one of these channels, to wit 8, serving to supply fuel during normal operation, whereas the other one, to wit 81, is intended to be used for starting the engine. This channel 81 extends to the upper end of cylindrical member 2. In other words, for channel 81, d=0. Channels 8 and 81 are, for instance, diametrally opposed.

The system works in the following manner:

In the relative position of the parts shown by Fig. l, which corresponds to the engine starting period during which a supplementary feed is to be provided, channel 81 is cleared, at its lower end, by oblique edge I0, while, on the contrary, channel 8 cannot open simultaneously into chambers 4 and 9 (h being then smaller than d). If the pump and the engine run very slowly. the whole of the fuel supplied by piston I is caused to flow through channel 81, valve 5 being lifted slightly above its seat 1. The height over which channel 81 opens into the compression chamber 4 of piston I is calculated in such manner that the speed of the engine is limited to a value lower than a possible speed of utilization, as the feed of fuel is cut 01T as soon as said speed tends to be exceeded, since the lower end of channel 81 is then pushed into bore 3 at the end of the outward stroke but the amount of fuel thus delivered is subsequently sucked back, during the return stroke, from delivery chamber 9.

The engine being started, control member I4 is rotated to bring the regulating valve into a position such as illustrated by Fig. 2, where, as it can be` seen, supplementary feed channel 81 no longer opens into chamber 4 and can no longer allow fuel to flow therethrough. On the contrary, channel 8, intended for normal operation of the engine, is then sufficiently cleared by the lower edge of bore 3 to permit fuel to flow therethrough periodically; but the fuel now supplied to the engine is reduced by an amount corresponding to distance d (fuel sucked back during the return stroke). This amount therefore corresponds to the supplementary feed provided for starting, when channel 81 was in service.

By rotating more or less control member I4, it is possible to vary the height of the useful portion (IL-d) of channel 8, and therefore that of the section A B C through which fuel can flow (Fig. 5). It is therefore possible, in this way, to vary the limit speed for which the valve, in the position of Fig. 5, is driven into its bore so as to close said channel, thus ensuring temporary stopping of the flow, and therefore regulation of the speed.

Of course, the distributing edges of the regulator, i. e. in particular edges as it, may ce given any desired inclinations or shapes, so as to permit of obtaining in the best. conditions the type of regulation that is to be obtained. These edges are supposed to be carried, in the embodiment of Fig. 1, by bracing pieces such as 26, 21, suitably assembled with the pump body, these pieces being for instance kept in position by a cap 28 held tight by a nut 29. Channels 8 and 81 (the number of which might be higher than two if it were desired to obtain a flow rate curve with several successive horizontal portions) may be constituted by fiat or recessed faces obtained by milling in the cylindrical body of the regulating member. Figs. 9 and 10 show, in this respect, a valve provided with two flat faces forming channels 81 and 82 of different depths p and both limited at the top by a solid portion of a height equal to d; one of these channels might be used for idling speeds, the other for normal running speeds, both adjustable.

The section of channels 8, instead of being uniform over the whole height of member 2, might be variable.

Fig. 6 shows a modification which permits of varying h. and d simultaneously, by means of two oblique surfaces |01, |02, carried by an intermediate piece such as 36.

It will be seen that, in these conditions, the operation of the regulator is determined by the respective positions of the lower edge 30 and the upper edge 31 of channel 8 with respect to the corresponding edge of surfaces |01 and |02. These conditions are therefore variable in accordance with the angular position of member 2 with respect to its axis.

It will thus be possible to interrelate the output and the speed in accordance with a given law by suitably combining the relative inclinations of Of course, these inclined surfaces may be of any desired form, with suitable curvilinear shapes, or, on the contrary, be provided with discontinuous portions, slopes, bevels, in combination with channel or channels 8 which may also be of suitable shapes.

Parallelism of the end faces of the pump body is ensured by two end pieces such as 38 and 39.

It is further possible, according to another embodiment, illustrated by Fig. 3, in order to make it possible to vary h and d simultaneously, to provide for an adjustment of the length of member 2. Valve head 5 is connected with member 2 through a screw I I engaged in the threaded bore of member 2 and cooperating with a counterscrew I2. In this case also it is possible to act both upon the output (through d) and upon the feed (through h).

In the embodiment of Fig. 4, the active length of the bore is made variable; for instance its lower edge I0 is moved, in particular by interposition of a packing I3 of variable thickness.

The device of Fig. 4 advantageously includes, at the base of member 2, a closing valve constituted by a ball 2l held in its end with a certain play and adapted to cooperate with a seat 25.

It will be seen that in this case, height d depends upon the thickness e of joint I3. Therefore it suilices to change the value of this joint to vary the corresponding volume. This joint might even by constituted by an elastic material the thickness of which is gradually varied by screwing or unscrewing a suitable assembling nut.

Figs. '7 and 8 illustrate another embodiment according to which adjustment of the section of s iiow takes place transversely to the axis o f valve.

Supposing that the lower edge of the bore is at right angles tc the axis I provide, on one side of bore 3, a cavity 80 oi' any suitable shape, for instance of cylindrical shape, at least one of the free edges of which, for instance 8I, is adapted to cooperate with channel 8, supposed in this case to be constituted by the space betweenthe wall of bore 3 and a iiat recess formed in member 2.

As shown by the section of Fig. 8, when valve member 2 is rotated about its axis, for instance from the position in solid lines into the dotted lines position, the distance between the edge 6I of cavity 60 and the corresponding inlet edge of passage 8 varries from a to"b, that is to say is caused to increase. It follows that the regulation action is modified.

On the drawing, it has been supposed that the height, such as h1, existing between the edge `3l! of channel 8 and the end face 62 oi' cavity 60 is not modi-ned when the valve member is rotated about its axis, but the arrangement might be diierent. f'

It is of course necessary to permit liquid to enter cavity 60, for which purpose bore 3 is connected to pump body I through an intermediate piece 63 the bore oi?A which is of a diameter larger than that of valve member 2.

This valvemember 2, in Fig. 7, is shown in a diagrammatic manner, with its piece or collar 64 subjected to theaction of spring 6.

It should be noted that, in the various embodiments illustrated, I have shown by way of example a piston I which provides itself for its distribution, fuel flowing in through an orifice I1 which is closed by saidpiston at thebeginning of its stroke and which is reopened near the end of its stroke by a groove I8 in communication, at I8c, with the end face of the piston, according to a known arrangement. The distribution surfaces are supposed to be at right angles to the axis; but they might be oblique when a relative rotation oi' piston I with respect to orifice I1 is to take place for adjusting the supply and/or the lead or end oi' injection.

Generally it will be advisable to control this piston I in such manner that its speed is accelerated at the beginning of its stroke corresponding to the closing of orices I1 or to the placing under pressure of the fuel and that it is on the contrary slowed down during the stroke portion corresponding to injection proper, which can easily be obtained by suitably determining the prole of cam I9 or the like.

This operation seems to be particularly advantageous since, during the first of these strokes, the energy required from the cam corresponds practically but to the accelerationlof the moving masses, whereas, during the second portion, the effort that is required is considerable due to the existance of the injection pressure.

Furthermore, the iirst of these strokes corresponds, during the starting period, to injection of the supplementary charge through channel 8, when two channels 8, 81 are provided (Figs. 1 and 4), which injection is advantageously the . caused to take place at an accelerated rate, on account of the fact that the engine is then running at low speed. On the other hand, during normal operation, this stroke takes place without substantial discharge pressure, because it corresponds to valve member 2 being driven in so as to compensate for the volume of fuel to be sucked back, whereby acceleration involves no inconvenience despite the higher speed of running oi' the engine and therefore oi' piston I. Normal injection takes place only .after said valve member has moved in a distance equal to d, and cam I9 can be calculated in such manner that the accelerating portion of its profile has already, at this time, ceased to act, so that piston I is actuated, for injection, at a rate which is, on the contrary, more moderate.

It should be noted that this acceleration of piston I during thev first portion of its stroke is also advantageous when the regulating valve member is movable chiefly through its inertia. as this inertia is increased by said acceleration, which improves sensitiveness.

It has been supposed, in Fig. l, that injection takes place through two channels 2Il and 2|, toward a discharge conduit 22, said channels being brought into communication with each other through a groove 23, this arrangement being disclosed merely by way of indication.

In a pump oi' the kind of those above described, in particular with reference to Fig. l. it isto be noted that the operation of the speed regulating valve member 2 produces a residual or parasitic injection, resulting from the fact that, during the operative period ofthe regulator, liquid passes between edges such as I0 and 38, during the very short time there isan open passage between said edges.

It may therefore be of interest to compensate for-this parasitic injection, for which purpose, according to another feature of my invention, means are provided for discharging the delivery conduit when this injection can take place.

For instance, this discharge is` carried out by means of the piston I of the pump, suitably arranged. l

As shown by Fig. 11, the end of injection, instead of being determined, as on Fig. 1, by means of a groove I8 communicating at |80 with the piston end face and cooperating with orifice I1, which serves both to admission and to backilow at the end of the injection, is obtained by means of a groove 23 which is not connectedwith the piston end face and cooperates at the end with the discharge channel 22 and with a special backfiow oriiice 33.

The liquid, driven from chamber 8, ilows through a conduit 20 which leads to an oriilce 32o, adapted to be, near the end of the upward stroke of the piston, locatedopposite a groove 23 thereof, which groove is not connected with compression chamber 4 and can cooperate. through its upper edge 32, with.4 an orifice 33 which ensures return toward chamber 3|.

Furthermore, the same groove 23, invcommunication with a lateral passage 34, can ensure, during the useful stroke of the piston. communication is of lesser importance than the amounts that flow back, there is no longer any parasitic amount of fuel delivered toward the injector since the injection end distribution will be opened before the beginning of said parasitic injection. Of course persons skilled in the art can easily determine the adjustment which will be considered by them as most advantageous.

It should further be noted that the above features have the advantages produced by so-called equi-current arrangements.

This is due to the fact that oriflces Il, which are provided for inflow of fuel into the pump body are no longer subjected to the effect of the back flow of fuel at the end of injection, nor to the eddies that result therefrom, a fact which, in particular, is favorable for filling the cyclinder at high speed of operation; furthermore, the liquid always flows in the same direction through regulator 2, valve 35 and groove 23, so that it produces an automatic evacuation of the gases that may accumulate, which can but facilitate the starting of the pump.

The above arrangement applies to all regulators in which residual injection takes place at the -beginning of the main injection period; it is then the new distribution disposed on the downstream side of the regulator above described which will close so as to shunt off the parasitic injection from the injection circuit.

Fig. 12 shows a regulator of this kind in which of said valve member being provided with at least one longitudinal recess adapted to form, together the regulating member is constituted by a piston 2 movable against the action of a spring 6 in the upper pump body, this piston 2 including a lateral leakage channel 50 and being adapted to cooperate with a return channel 5|.

Parasitic injection takes place in this case when intake channel l1 is closed by the upper face of piston l.

In order to cancel the effect of this parasitic injection, a return channel suchas 33 is arranged to cooperate with the lower face 5| of the piston groove 23. This parasitic injection is thus shunted ofi' through passage 23, whereas true injection takes place from the time when said passage 33 is closed by edge 5I fuel being distributed toward the corresponding conduit 22 through lateral passage 34.

Passage 33, on the one hand, the orifice 320 of conduit 22, on the other hand, and, finally,

face 5I (which may be either straight or oblique) will be of course suitably arranged for ensuring correct operation, continuity of injection toward the corresponding conduit 23 having to be maintained after the closing of passage 33.

In a general manner, While I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An injection pump for an internal combustion engine which comprises, in combination, a fixed frame provided with a compression chamber, a delivery chamber, and a bore extending between said two chambers, a piston in said compression chamber, a valve member slidable longitudinally in said bore, spring means for yieldably opposing movements of said valve member toward said delivery chamber, the side wall with the inner wall of said bore, a longitudinal channel for the flow of liquid along said valve member from said compression chamber toward said delivery chamber, and means operable at will for modifying the useful sections of flow of the liquid through said channel, to permit of modifying the action thereof.

2. An injection pump for an internal combustion engine which comprises, in combination, a fixed frame provided with a compression charnber, a delivery chamber, and a bore extending between said two chambers, a piston in said compression chamber, a valve member slidable longitudinally in said bore, spring means for yieldably opposing movements of said valve member toward said delivery chamber, the side wall of said valve member being provided with at least one longitudinal recess adapted to form, together with the inner wall of said bore, a longitudinal channel for the flow of liquid along said valve member from said compression chamber toward said delivery chamber, the lower edge of said longitudinal recess being located above the lower edge of said valve member, and these edges being adapted to modify the section of flow for the fuel according to the angular position of said valve member about its axis with respect to said bore, and means operable at will for adjusting said angular position.

3. An injection pump according to claim 2 in which the edge of said bore, at the end thereof where it opens into said compression chamber, is oblique to its axis.

4. An injection pump for an internal combustion engine which comprises, in combination, a xed frame provided with a compression chamber, a delivery chamber, and a bore extending between said two chambers, a piston in said compression chamber, a valve member slidable longitudinally in said bore, spring means for yieldably opposing movements of said valve member toward said delivery chamber, the side wall of said valve member being provided with two longitudinal recesses each adapted to form, together with the inner wall of said bore, a longitudinal channel for the flow of liquid along said valve member from said compression chamber toward said delivery chamber, and means operable at will for modifying the useful sections of ow of the liquid through said channels, so that each of them is out of operation when the other is transmitting liquid.

5. An injection pump for an internal combustion engine which comprises, in combination, a fixed frame provided with a compression chamber, a delivery chamber, and a bore extending between said chambers, the diameter of said bore being smaller than those of said chambers, a piston in said compression chamber, a valve member including on the one hand a valve proper adapted to cooperate with the valve seat formed by the edge of said bore at the end thereof opening into said delivery chamber and on the other hand a cylindrical stem rigid with said valve proper and :fitting slidably in said bore, spring means for yieldingly opposing movements of said valve member toward said delivery chamber, the side wall of said cylindrical stem being provided with two longitudinal recesses each adapted to form, together with the inner wall of said bore, a longitudinal channel for the flow of liquid along said valve member from said compression chamber toward said delivery chamber, both oi said channels having their end edges, on the side of the compression chamber, located at a distance from the corresponding edge of the cylindrical stem, but at different levels, respectively, whereas one of said channels extends at the other end as far as said valve proper, and the other channel extends, at said other end, to a distance from said valve proper, the edge of said bore, at the end thereof where it opens into said compression chamber, being oblique to its axis, and means for adjusting at will the angular position of said stem about its axis with respect to said bore.

6. An injection pump according to claim further including adjusting means for varying at will the distance between the second end edge of the second mentioned channel and said valve proper.

7. An injection pump according to claim 5 in which said cylindrical stem is screwed on a threaded rod carried by the valve proper, so as to permit of varying at will the distance between the second end edge of the second mentioned channel and said valve proper.

8. An injection pump according to claim 2 in which said frame includes an intermediate piece between the compression chamber and the delivery chamber, the bore being formed in said intermediate piece which is of wedge-shaped axial section so that the edge of said bore, at the end thereof where it opens into said compression chamber, is oblique to the bore axis.

9. An injection pump according to claim 2 in which said frame comprises an intermediate structure provided with said bore between the compression chamber and the delivery chamber, said structure including, at the end thereof adjacent to said compression chamber, a portion provided with a hole forming a valve seat, and a valve carried by the end of said stem adapted to cooperate with said valve seat, said structure being of adjustable dimension in a direction parallel to the bore axis.

10. An injection pump according to claim 2 in which the edges of said bore, at the respective ends thereof, are both oblique to the axis thereof.

11. An injection pump for an internal combustion engine which comprises, in combination, a xed frame provided with a compression chamber, a delivery chamber, and a, bore extending between said two chambers, a piston in said compression chamber, a valve member slidable longitudinally in said bore, spring means for yieldably opposing movements of said valve member toward said delivery chamber, the side wall of said valve member being provided with at least one longitudinal recess adapted to form, together with the inner wall of said bore, a longitudinal channel for the iiow of liquid along said valve member from said compression chamber toward said delivery chamber, said valve member being further provided with a lateral cavity adapted to vary the section of flow of the liquid from said compression chamber to said channel when said valve member is rotated about its axis, and means operable at will for modifying the angular position of said valve member about its axis with respect to said bore.

12. An injection pump according to claim 1 including a delivery conduit in communication with said delivery chamber and means for automatically discharging said delivery conduit for the time said valve member is liable to give parasitic injection.

13. An injection pump according to claim 1 including a delivery conduit in communication with said delivery chamber and means operative in cooperation with a portion of the piston for discharging said delivery conduit at the end of the piston stroke toward said valve member.

14. An injection pump according to claim 1 including a delivery conduit in communication with said delivery chamber and means operative in cooperation with a portion of the piston for discharging said delivery conduit at the end of the piston stroke toward said valve member, said means including a regulating check valve including a lateral passage, a discharge orifice arranged to cooperate with said check valve and means carried by said piston for delaying the beginning of injection.

15. An injection pump according to claim l including a delivery conduit in communication with said delivery chamber and means operative in cooperation with a portion of the piston for discharging said delivery conduit at the end of the piston stroke toward said valve member,A said means including a regulating check valve including a lateral passage, a discharge oriilce arranged to cooperate with said check valve and means carried by said piston for delaying the beginning of injection, said means being arranged so that, after the piston has cut oi liquid inflow, the delivery conduit still remains in communication with the liquid feed during a certain movement of the piston.

YVES ANDR GRIMOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

